The post unleashed a torrent of generosity. More than 600 blankets have been donated to Crystal's school, according to KTRK-TV. School staff hope to get about 720 — enough to send one home with every student.

Last school year, 96 percent of the students on campus were considered economically disadvantaged, according to Texas Education Agency statistics.

Crystal wrote her letter after Espiricueta explained to her students the difference between a want and a need. She instructed the children to ask Santa for two wants and one need.

"I started reading them and it's like, I did not expect her to say, 'I need food. I want food, but I need a blanket more,'" Espiricueta told KGBT-TV. "And I asked, 'Well, why do you need a blanket more than the food?' 'Well, I get to eat at school — sometimes I may not have at home, but I get to eat at school. A blanket I have one, but it's not warm enough.'"

One donor, Nashley Garcia of McAllen, read Espiricueta's post and assumed the student who wrote the letter was a boy because of the ball, The Washington Post reported. She brought an Avengers blanket and three types of balls.

As Garcia dropped off the gifts, Espiricueta introduced her to Crystal. The girl told Garcia that she wanted the ball for her brother, according to The Post.

Crystal lives with her brother and her mother, Maria Isabel Cortez, a single parent.